This invention relates to a signal recording apparatus, and is particularly usable in editing a video image recorded on a magnetic tape.
As shown in FIG. 1, in a conventional video tape recorder, magnetic heads 1A, 1B scan a magnetic tape 2 which is longitudinally fed obliquely to form recording tracks T1, T2, . . .
Further, a control track CTL is formed by a control head 3 in a bottom end of the magnetic tape 2.
Field images are sequentially formed on the recording tracks T1, T2, . . . by the magnetic heads 1A, 1B and a control signal is recorded in the control track CTL in response to a commencement of recording of the recording tracks T1, T2 . . .
In reproduction, the video tape recorder responds to a level of reproduction RF signal detected by the magnetic heads 1A, 1B scanning the recording tracks T1, T2 . . . to control such that the magnetic heads 1A, 1B scan the recording tracks T1, T2, . . . without deviation therefrom.
That is, the video tape recorder detects a deviation of the magnetic heads 1A, 1B from the recording tracks T1, T2, . . . by a variation of a signal level of the RF signal and sends a control signal for controlling phase of the control signal detected through the control heads 3 to a capstan motor to control a rotational phase of the capstan motor.
A running speed of the magnetic tape 2 is corrected by the rotational phase of the capstan motor and the video tape recorder controls the magnetic heads 1A, 1B such that they scan the recording tracks T1, T2, . . . without deviation.
When an image recorded on the magnetic tape 2 is edited, the video tape recorder positions the magnetic heads 1A, 1B in edition start tracks on the basis of a detection level of the RF signal detected by a recording track (referred to as edition start preceding track, hereinafter) which precedes by 1 track a recording track (referred to as edition start track, hereinafter), among the editing and recording tracks T1, T2, . . . , corresponding to an assigned editing point and records the edited image (FIG. 2A).
In FIGS. 2A to 2C, the tracks formed obliquely on the tape is illustrated schematically so as to be in a row vertically.
However, there may be a case where a tracking error .DELTA.H of the magnetic heads to the edition start track of the edition image is produced by a detection error of the control signal due to extension of the magnetic tape 2 and/or an error due to a relation between a track width and a gap width of the magnetic head.
When the edition start track corresponds to the recording track T2, the edition track after the edition start deviates by .DELTA.H with respect to the edition start track 2 as shown in FIG. 2B and edition tracks T12, T13, T14, . . . are formed sequentially from this position.
Further, when a recording of another image signal is started with the edition track T13 as a second edition start track, the edition tracks T23, T24, T25, . . . after the second edition deviate with respect to the edition start track T13 by .DELTA.H, as shown in FIG. 2C.
At this time, the edition tracks T23, T24, T25 after the second edition deviate by 2.times..DELTA.H with respect to unedited recording tracks T3, T4, T5, . . .
Similarly, the deviation is accumulated with repetitive edition works and, after N editions, recording tracks TNM, TNM+1, TNM+2, . . . may deviate by N.times..DELTA.H with respect to unedited recording tracks TM, TM+1, TM+2, . . .
Such tracking deviation causes an image disturbance on a screen when a peripheral portion of an editing point is reproduced by the video tape recorder.